The transport of this type of fluid, in particular from a liquefaction unit to a transport vessel or from a transport vessel to a storage unit, is generally carried out by means of a flexible fluid transporting pipe having an internal diameter of the order of 400 mm in a manner so as to ensure a high throughput and rapid transfer.
Flexible pipes used for these operations in an off-shore environment are most often classified into two categories, aerial flexible pipes, and floating or underwater flexible pipes.
In the case of a side by side type transfer configuration in which the boat is brought alongside a quay or a floating unit, the aerial flexible pipe has a length of around 40 to 70 meters. In the case of a tandem configuration in which the vessel is brought to the stern or bow of the floating unit, the vessel and the floating unit being substantially aligned, the aerial flexible pipe has a length of around 100 to 170 meters. The side by side configuration requires a flexible pipe that is stronger than that in the other configuration.
For a transfer between a ship and a floating unit, by means of a floating or underwater flexible pipe, the flexible pipe has a length which can go up to approximately 350 meters. These floating or underwater pipes are generally pipes that are used in the harshest of conditions on account of a lower bending radius and being subjected to a higher dynamic load due in particular to the movement of floating supports as well as to the leak proof sealing that is more difficult to control with respect to the external environment given that the flexible pipe may be submerged.
In a general manner, the flexible pipe comprises of several layers from the inside to the outside, namely:                a corrugated inner tube, defining a plurality of corrugations leading radially towards the axis,        at least one tensile armour layer, arranged around the corrugated tube,        at least one thermal insulation layer arranged around the armour layer, and        a leak proof sealed external sheath.        
The flexible pipe may also include an leak proof sealed intermediate sheath fabricated by means of winding and bonding of rubber strips, or by extrusion of a polymeric material, and disposed between two layers of thermal insulation.
The leak proof sealed external sheath is fabricated by means of winding and bonding of rubber strips, or with two polymeric tubular sheaths extruded one over the other.
The flexible pipes also have connecting end fittings intended for connecting them to one another or with the terminal equipment and these end fittings must be manufactured under conditions that ensure both optimal fastening as well as good leak proof sealing.
Indeed, the connecting end fittings must perform several functions that include fixing of the end of the corrugated tube, anchoring of the tensile armour as well as thermal protection of the external sheath and the means for crimping this external sheath.
For this purpose, the connecting end fittings comprise a front part including an array of elements, and in particular a front end flange for holding in place the corrugated tube and elements for fixing the armour layer. The connecting end fittings also comprise a rear part formed by at least one rear end flange for crimping the external sheath and for holding in place the thermal insulation layers. The front end and rear end flanges, respectively, are connected to each other by connecting elements in a manner so as to ensure cohesion between the front and rear parts of the connecting end fitting.
The external sheath is generally comprised of polymers that become brittle at low temperatures, and in practice should not be subjected to temperatures below −20° C.
In the main part of the flexible pipe, that is to say, between the two ends, the thermal insulation layers make it possible to ensure that the cryogenic fluid which is at a temperature of about −160° C., is prevented from excessively cooling the external sheath.
However, the thermal insulation layers are terminated at the level of each end fitting, which could eventually cause a rupture of the thermal bridge at the crimping area of the external sheath and thus excessively cool the end of the external sheath.
The invention aims to provide a connecting end fitting for a flexible pipe which makes it possible to avoid this type of problem by means that are simple to implement.